The invention provides a wearable elbow-joint-rehabilitation-training and life-assisting device. The wearable elbow-joint-rehabilitation-training and life-assisting device is characterized by comprising an upper-arm fixing portion for fixing the upper arm of a patient, a connecting portion connected with the upper-arm fixing portion, a speed reduction motor which is arranged in the connecting portion and has the driving effect, a transmission unit connected with the connecting portion and the speed reduction motor, a front-arm rotating portion, a front-arm fixing portion connected with the front-arm rotating portion and used for fixing the front arm of the patient, a control portion and an upper-arm shell, wherein the front-arm rotating portion is connected with the transmission unit, rotates under driving of the speed reduction motor, and comprises a limiting sliding groove for limiting the front-arm rotating portion to rotate in the certain angle range; the control portion is connected with the speed reduction motor, controls the speed reduction motor, and comprises a signal generating unit for generating and outputting PWM signals, a driving unit for processing the PWM signals and driving the speed reduction motor and a feedback potentiometer connected with the transmission unit and the driving unit and used for feeding back the rotating position of the front-arm rotating portion; the connecting portion is sleeved with the upper-arm shell.